1 /* 2 * linux/fs/readdir.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/module.h> 9 #include <linux/time.h> 10 #include <linux/mm.h> 11 #include <linux/errno.h> 12 #include <linux/stat.h> 13 #include <linux/file.h> 14 #include <linux/fs.h> 15 #include <linux/dirent.h> 16 #include <linux/security.h> 17 #include <linux/syscalls.h> 18 #include <linux/unistd.h> 19 20 #include <asm/uaccess.h> 21 22 int vfs_readdir(struct file *file, filldir_t filler, void *buf) 23 { 24 struct inode *inode = file->f_path.dentry->d_inode; 25 int res = -ENOTDIR; 26 if (!file->f_op || !file->f_op->readdir) 27 goto out; 28 29 res = security_file_permission(file, MAY_READ); 30 if (res) 31 goto out; 32 33 res = mutex_lock_killable(&inode->i_mutex); 34 if (res) 35 goto out; 36 37 res = -ENOENT; 38 if (!IS_DEADDIR(inode)) { 39 res = file->f_op->readdir(file, buf, filler); 40 file_accessed(file); 41 } 42 mutex_unlock(&inode->i_mutex); 43 out: 44 return res; 45 } 46 47 EXPORT_SYMBOL(vfs_readdir); 48 49 /* 50 * Traditional linux readdir() handling.. 51 * 52 * "count=1" is a special case, meaning that the buffer is one 53 * dirent-structure in size and that the code can't handle more 54 * anyway. Thus the special "fillonedir()" function for that 55 * case (the low-level handlers don't need to care about this). 56 */ 57 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de))) 58 59 #ifdef __ARCH_WANT_OLD_READDIR 60 61 struct old_linux_dirent { 62 unsigned long d_ino; 63 unsigned long d_offset; 64 unsigned short d_namlen; 65 char d_name[1]; 66 }; 67 68 struct readdir_callback { 69 struct old_linux_dirent __user * dirent; 70 int result; 71 }; 72 73 static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset, 74 u64 ino, unsigned int d_type) 75 { 76 struct readdir_callback * buf = (struct readdir_callback *) __buf; 77 struct old_linux_dirent __user * dirent; 78 unsigned long d_ino; 79 80 if (buf->result) 81 return -EINVAL; 82 d_ino = ino; 83 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { 84 buf->result = -EOVERFLOW; 85 return -EOVERFLOW; 86 } 87 buf->result++; 88 dirent = buf->dirent; 89 if (!access_ok(VERIFY_WRITE, dirent, 90 (unsigned long)(dirent->d_name + namlen + 1) - 91 (unsigned long)dirent)) 92 goto efault; 93 if ( __put_user(d_ino, &dirent->d_ino) || 94 __put_user(offset, &dirent->d_offset) || 95 __put_user(namlen, &dirent->d_namlen) || 96 __copy_to_user(dirent->d_name, name, namlen) || 97 __put_user(0, dirent->d_name + namlen)) 98 goto efault; 99 return 0; 100 efault: 101 buf->result = -EFAULT; 102 return -EFAULT; 103 } 104 105 SYSCALL_DEFINE3(old_readdir, unsigned int, fd, 106 struct old_linux_dirent __user *, dirent, unsigned int, count) 107 { 108 int error; 109 struct file * file; 110 struct readdir_callback buf; 111 112 error = -EBADF; 113 file = fget(fd); 114 if (!file) 115 goto out; 116 117 buf.result = 0; 118 buf.dirent = dirent; 119 120 error = vfs_readdir(file, fillonedir, &buf); 121 if (buf.result) 122 error = buf.result; 123 124 fput(file); 125 out: 126 return error; 127 } 128 129 #endif /* __ARCH_WANT_OLD_READDIR */ 130 131 /* 132 * New, all-improved, singing, dancing, iBCS2-compliant getdents() 133 * interface. 134 */ 135 struct linux_dirent { 136 unsigned long d_ino; 137 unsigned long d_off; 138 unsigned short d_reclen; 139 char d_name[1]; 140 }; 141 142 struct getdents_callback { 143 struct linux_dirent __user * current_dir; 144 struct linux_dirent __user * previous; 145 int count; 146 int error; 147 }; 148 149 static int filldir(void * __buf, const char * name, int namlen, loff_t offset, 150 u64 ino, unsigned int d_type) 151 { 152 struct linux_dirent __user * dirent; 153 struct getdents_callback * buf = (struct getdents_callback *) __buf; 154 unsigned long d_ino; 155 int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 2, sizeof(long)); 156 157 buf->error = -EINVAL; /* only used if we fail.. */ 158 if (reclen > buf->count) 159 return -EINVAL; 160 d_ino = ino; 161 if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { 162 buf->error = -EOVERFLOW; 163 return -EOVERFLOW; 164 } 165 dirent = buf->previous; 166 if (dirent) { 167 if (__put_user(offset, &dirent->d_off)) 168 goto efault; 169 } 170 dirent = buf->current_dir; 171 if (__put_user(d_ino, &dirent->d_ino)) 172 goto efault; 173 if (__put_user(reclen, &dirent->d_reclen)) 174 goto efault; 175 if (copy_to_user(dirent->d_name, name, namlen)) 176 goto efault; 177 if (__put_user(0, dirent->d_name + namlen)) 178 goto efault; 179 if (__put_user(d_type, (char __user *) dirent + reclen - 1)) 180 goto efault; 181 buf->previous = dirent; 182 dirent = (void __user *)dirent + reclen; 183 buf->current_dir = dirent; 184 buf->count -= reclen; 185 return 0; 186 efault: 187 buf->error = -EFAULT; 188 return -EFAULT; 189 } 190 191 SYSCALL_DEFINE3(getdents, unsigned int, fd, 192 struct linux_dirent __user *, dirent, unsigned int, count) 193 { 194 struct file * file; 195 struct linux_dirent __user * lastdirent; 196 struct getdents_callback buf; 197 int error; 198 199 error = -EFAULT; 200 if (!access_ok(VERIFY_WRITE, dirent, count)) 201 goto out; 202 203 error = -EBADF; 204 file = fget(fd); 205 if (!file) 206 goto out; 207 208 buf.current_dir = dirent; 209 buf.previous = NULL; 210 buf.count = count; 211 buf.error = 0; 212 213 error = vfs_readdir(file, filldir, &buf); 214 if (error >= 0) 215 error = buf.error; 216 lastdirent = buf.previous; 217 if (lastdirent) { 218 if (put_user(file->f_pos, &lastdirent->d_off)) 219 error = -EFAULT; 220 else 221 error = count - buf.count; 222 } 223 fput(file); 224 out: 225 return error; 226 } 227 228 struct getdents_callback64 { 229 struct linux_dirent64 __user * current_dir; 230 struct linux_dirent64 __user * previous; 231 int count; 232 int error; 233 }; 234 235 static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, 236 u64 ino, unsigned int d_type) 237 { 238 struct linux_dirent64 __user *dirent; 239 struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; 240 int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 1, sizeof(u64)); 241 242 buf->error = -EINVAL; /* only used if we fail.. */ 243 if (reclen > buf->count) 244 return -EINVAL; 245 dirent = buf->previous; 246 if (dirent) { 247 if (__put_user(offset, &dirent->d_off)) 248 goto efault; 249 } 250 dirent = buf->current_dir; 251 if (__put_user(ino, &dirent->d_ino)) 252 goto efault; 253 if (__put_user(0, &dirent->d_off)) 254 goto efault; 255 if (__put_user(reclen, &dirent->d_reclen)) 256 goto efault; 257 if (__put_user(d_type, &dirent->d_type)) 258 goto efault; 259 if (copy_to_user(dirent->d_name, name, namlen)) 260 goto efault; 261 if (__put_user(0, dirent->d_name + namlen)) 262 goto efault; 263 buf->previous = dirent; 264 dirent = (void __user *)dirent + reclen; 265 buf->current_dir = dirent; 266 buf->count -= reclen; 267 return 0; 268 efault: 269 buf->error = -EFAULT; 270 return -EFAULT; 271 } 272 273 SYSCALL_DEFINE3(getdents64, unsigned int, fd, 274 struct linux_dirent64 __user *, dirent, unsigned int, count) 275 { 276 struct file * file; 277 struct linux_dirent64 __user * lastdirent; 278 struct getdents_callback64 buf; 279 int error; 280 281 error = -EFAULT; 282 if (!access_ok(VERIFY_WRITE, dirent, count)) 283 goto out; 284 285 error = -EBADF; 286 file = fget(fd); 287 if (!file) 288 goto out; 289 290 buf.current_dir = dirent; 291 buf.previous = NULL; 292 buf.count = count; 293 buf.error = 0; 294 295 error = vfs_readdir(file, filldir64, &buf); 296 if (error >= 0) 297 error = buf.error; 298 lastdirent = buf.previous; 299 if (lastdirent) { 300 typeof(lastdirent->d_off) d_off = file->f_pos; 301 if (__put_user(d_off, &lastdirent->d_off)) 302 error = -EFAULT; 303 else 304 error = count - buf.count; 305 } 306 fput(file); 307 out: 308 return error; 309 } 310